How a TBM works
Click on image to discover TBM parts
Cutterhead
This is the part that rotates and excavates the soil.
Air Lock
Acclimatises workers prior to entering and exiting the pressurised excavation chamber.
TBM Hydraulic Thrust Jacks
These jacks push the whole TBM forward by creating pressure against the installed precast concrete lining segments. This is what makes it all move forward.
Tail Skin
Protective steel skin within which the segmented precast tunnel lining is built. This area is sealed to prevent groundwater entering behind the lining.
TBM Conveyor
This is a conveyor belt system that transports excavated material away from the screw conveyor discharge to the tunnel conveyor.
Electrical Control Container
Houses the panels for the distribution and control of electrical power to the TBM’s many components.
Electrical Transformer
Changes the voltage of the incoming electrical power to a lower usable power for the motors. The electrical power runs from the transformer to the electrical control centre.
TBM Control Cabin
This is where the entire TBM and associated systems are operated (the TBM’s cockpit).
Tunnel Conveyor Transfer
This is where the tunnel spoil changes from the TBM conveyor to the tunnel conveyor belt.
Ventilation Ducts
This provides a constant flow of clean air and maintains a safe temperature for the workers.
Refuge Container
This is a safety refuge for underground personnel.
Ventilation Canister
Stores 200m of ducts which feed out as the TBM advances – similar to a telescope unfolding.
Tunnel Conveyor Belt
Material is transferred onto a conveyor belt that runs along the length of the tunnel up to the surface. Excavated material is then stockpiled on the surface and transported by trucks to designated fill sites.
Toilets
Multi Service Vehicle (MSV)
Carries precast lining segments from the surface to the TBM. Also used to transport personnel in the tunnel.
Segment Crane
Lifts precast lining segments from the MSV then rotates and carries them to the segment feeder.
Bentonite Tank
Storage for ground conditioning fluids.
Bentonite Pumps
Waste Water Tank
Compressors
Provides compressed air for air tools.
Cooling Unit
Hose Reels
Grease Pumps
Used for sealants and lubrication.
Hydraulics
Powers TBM hydraulic systems.
Segment Feeder
This is a transfer system for precast tunnel lining segments.
Tunnel Lining
Concrete segments that form the tunnel.
Segment Lining Erector
This machine works just like a big robot arm. It picks up the concrete lining segments using a vacuum plate and then rotates and places them into position to form a ring.
Main Drive Unit
This unit houses the main bearing (powered by several motors) and turns the cutterhead.
Screw Conveyor
Lifts excavated material from the excavation chamber up to the TBM conveyor. It also enables operation of an earth pressure balance system used for excavating soft material. It essentially maintains the ground support and controls the excavated material transfer.